Pharmacological activities of some Argyranthemum species growing in the Canary Islands.

Methanolic extracts of eight subspecies of genus Argyranthemum were evaluated against brine shrimps, human cancer cell lines, malarial parasites and microorganisms under in vitro conditions. In the shrimp assay, samples of A. adauctum ssp. adauctum, A. adauctum ssp. erythrocarpon and A. frutetescens ssp. succulentum were active with ED50 values in the range of around 300 to 360 microg/ml. In the Caco-2, HepG2 and MCF-7 cell lines, the samples A. adauctum ssp. jacobaeifolium and A. adauctum ssp. palmensis were active with LC50 values ranging between 80-90 microg/ml. The secondary assay results of antimalarial activity of samples, A. adauctum ssp. adauctum, A. adauctum ssp. dugourii, A. adauctum ssp. erythrocarpon and A. adauctum ssp. jacobaeifolium have IC50 values <50 microg/ml. The samples demonstrated broad specific antimicrobial activity against five different microorganisms.

Cytotoxic activities of some Greek Labiatae herbs.

Nineteen methanolic crude plant extracts of Labiatae family, collected in Greece from different locations, were evaluated for cytotoxic activity against brine shrimps and three human cancer cell lines along with a normal mouse cells as a control cell line. In the brine shrimp lethality test, Mentha pulegium was the only sample found to be active with an LC(50) value 347.3 micro g/ml, while all remaining samples had LC(50) values greater than 1000 micro g/ml. In case of Caco-2 and HepG2 cell lines, only one sample, namely Thymus parnassicus Halacsy, was active with LC(50) values 44.6 and 50.3 micro g/ml respectively, while against MCF-7 cell line, two samples, namely, Clinopodium vulgare L. (LC(50): 60.4 micro g/ml), and Thymus parnassicus Halacsy (LC(50): 54.7 micro g/ml), were found active.

Antioxidant and cytotoxic activities of Hypericum sp. on brine shrimps and human cancer cell lines.

Ten different samples of five Hypericum sp. were tested on brine shrimps, human colon carcinoma and human hepatoma cell lines for their cytotoxic activities. H. triquetrifolium Turra. (Rafina) showed the highest activity (LC50 = 22 mg/mL) on brine shrimps, while the extracts of the other nine samples showed significant to moderate activities (LC50 from 37 to 107 mg/mL). H. empetrifolium Wild. (Parnon) showed the highest activity in human colon carcinoma and human hepatoma cell lines, with LC50 values 29 and 25.1 mg/mL, respectively, while the LC50 values of the other samples were more than 45 mg/mL. It is very interesting to observe that most Hypericum samples showed good antioxidant activity in vitro.

Licania michauxii Prance root extract induces hsp 70 mRNA and necrotic cell death in cultured human hepatoma and colon carcinoma cell lines.

An extract of Licania michauxii Prance root was found to be cytotoxic to cultured human hepatoma (HepG2) and colon carcinoma (Caco-2) cells. Morphological and nuclear characteristics of treated cells were consistent with necrotic death. Increases in the chaperone protein hsp 70 and hsp 70 mRNA were dose dependent reaching peak mRNA levels (40-fold above control) at 6 h. Increases in nuclear localization of hsp 70 was also observed with treatment. Heat treatment of cells for 45 min to induce hsp 70 prior to treatment with the extract provided transient protection from the necrotic response.

Partial characterization of an abundant human skin melanosomal 66 kDa protein (MP 66) and investigation to purify a similar protein from B16 murine melanoma tumours.

A single polypeptide protein of molecular weight 66kDa (MP 66), purified to homogeneity from melanosomes of normal human cadaver skin epidermal melanocytes, was further characterized. Based on the yield in the present investigation, the intracellular concentration of this protein was calculated to be 4.2 microM. It was shown to be a glycoprotein on gel electrophoresis. Based on its partial N-terminal amino acid sequence, it was shown to be distinct from known melanosomal proteins such as gp 75, tyrosinase-related protein-2 (TRP-2) and Pmel 17. Investigation to purify a similar type of protein from B16 murine melanoma tumours by following the same purification procedure resulted in a partially purified protein with a molecular weight of 66 kDa. However, unlike MP 66, this protein did not show inhibition of the monophenolase activity of tyrosinase at pH 6.8. Finally, the effects of 0.5 mM each of CaCl2, ZnSO4 and FeSO4 together, and of human skin epidermal melanosomal proteins, were studied on melanin polymerization at pH 4.7. The metal cations failed to initiate melanin polymerization, while melanosomal proteins did in a dose-dependent manner.